Brisket is far and away the most difficult thing to cook properly, especially on a smoker. I expect better from the commercial places since they generally have easily controllable smokers, but the tough thing for them is making enough for the demand yet finishing it as demands ramps up so the meat doesn't have to sit very long, which dries it out fast. But for a backyard smoker like me it is the pinnacle of the craft. I have actually built a home made insulation sleeve for my smoker specifically for brisket. Brisket is very sensitive to temperature fluctuations. Too high of heat for too long (as little as an hour at 30 degrees over target) can ruin the final product. You need to hold it to a pretty damn tight 15 degree range if you have a hope of getting something good in the end. For me the brisket is the measure of a good bbq joint. Now if they can do great brisket but their other stuff is just ok then it is probably a matter of not really understanding the meat that well overall. Brisket and pork butt and ribs all require different applications to get the best product, all the way down to brines and spice rubs. It is really as much as art as a science in the end.